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Friday, March 8, 2019

Retrospective #20: Know Your Dietary Fats: Saturated and Unsaturated

“Let food be thy medicine
and medicine be thy food”: Hippocrates (460BC - 370BC). If you are going to
take an interest in your health, as the “father of medicine” sagely advised,
you need a basic understanding of nutrition.

So, let’s begin with the
classification of fats into Saturated
and Unsaturated. Saturated fats are
solid at room temperature and unsaturated fats are liquid. In the 2010 “Dietary
Guidelines for Americans,” the USDA/HHS has begun to use “saturated fat” and “solid
fat” interchangeably. In the HHS’s new “food pyramid”, the HHS never uses the macronutrient
word “fat.” It calls all unsaturated fats
“oils.” Do you find this nomenclature confusing? I do.

Saturated fats are for the most part animal fats, i.e. fats
found in intramuscular tissue as well as under the skin and around the organs. Both
in the animals we eat, and in our own physiology, fat serves as both an energy
source and an energy reserve. It also cushions the organs and skeleton from
damaging blows and insulates the body from cold.

More recently – and this
is a development of monumental importance in our understanding of fat
metabolism -- fat stores have come to be recognized as an endocrine organ as
well. Leptin, a hormone discovered in adipose (fat) tissue in 1994, is an
appetite suppressant, sending a strong signal to the hypothalamus at the center
of the brain. Our fat is in a constant state of flux as its primary form, triglyceride
molecules, are being created or broken down.

Two other saturated fats
(both solid at room temperature) that are commonly found in foods are vegetable in origin: Both are tropical
oils – coconut oil and palm oil. Coconut oil, a medium-chain saturated fat, is
appearing with increasing frequency in the Western Diet, but both have been
used in cooking for millennia in tropical regions.

Saturated fats are solid
because of their dense structure, with every carbon atom along the carbon chain
having two hydrogen atoms. In addition, as it has no “double bond” between
carbon atoms, they are straight, packed closely together and thus solid. Since
there are no “free” atoms, they are also very stable and are not liable to become rancid when exposed
to oxygen. It also means that, in their normal state or in cooking they will not create harmful “free radicals” or, when
heated, produce pro-inflammatory AGE’s (Advanced Glycation End-Products).

Unsaturated fats break
down into two sub-classes: monounsaturated
and polyunsaturated. Monounsaturated
fats are primarily found in olive oil, and to a lesser extent in Canola oil and
peanut oil. Additional sources are avocado and some popular nuts (macadamias,
pecans, hazelnuts). They are called monounsaturated because they have only one “double bond” in the carbon chain.
They are fairly tightly packed and fairly stable when heated or exposed to
oxygen (as in air). Have you noticed how olive oil becomes solid when
refrigerated? It is, therefore, safe to use.

Polyunsaturated fats are
fats that have more than one double
bond in the carbon chain (hence poly),
and are therefore loosely constructed and usually
found in the liquid state as “oils” (see the exception for trans fats below). Because of their loose construction, they are
relatively unstable, “reactive,” and rather easily become rancid. They are also
easily damaged by heating (as in a deep fryer) and especially when reheated
over and over.

These polyunsaturated
fats are the vegetable oils that are now ubiquitous in our food supply due to
their ability to be manufactured cheaply. But refining and processing also has
deleterious effects that are becoming increasingly known and understood. Trans fat is an example. It is a liquid
vegetable oil that has been “hydrogenated,” or “partially hydrogenated,” to
make it solid for use as margarine and in manufactured baked goods and cooking.
There is a now broad consensus that everyone
should strictly avoidartificialtrans fats. Read food labels carefully to avoid all hydrogenated oils
because portion size provides a “workaround” that is used to deceive us.

Finally, all fats are
combinations of all three types: saturated, monounsaturated
and polyunsaturated. Butter, for example is 66% saturated,
30% mono and 4% poly. Olive oil is 15%
saturated, 70% mono and 10% poly. Soybean
oil, used in 70% of processed foods and most restaurants in the US, is 15% saturated,
22% mono and 62% polyunsaturated (the worst!). Takeaway: Saturated and
monounsaturated fats: good. Polyunsaturated fats: bad!

About Me

I was diagnosed a Type 2 diabetic in 1986. I started a Very Low Carb diet (Atkins Induction) in 2002 to lose weight. I didn’t realize at the time that it would put my diabetes in clinical remission, or that I would be able to give up almost all of my oral diabetes meds. I also didn’t understand that, as I lost weight and continued to eat Very Low Carb, my blood lipids would dramatically improve (doubling my HDL and cutting my triglycerides by 2/3rds) and that my blood pressure would drop from 130/90 to 110/70 on the same meds.
Over the years I changed from Atkins to the Bernstein Diet (designed for diabetics) and, altogether lost 170 pounds. I later regained some and then lost some. As long as I eat Very Low Carb, I am not hungry and I have lots of energy. And I no longer have any of the indications of Metabolic Syndrome.
My goal, as long as I have excess body fat, is to remain continuously in a ketogenic state, both for blood glucose regulation and continued weight loss. I expect that this regimen will continue to provide the benefits of reduced systemic inflammation, improved blood lipids and lower blood pressure as well.